<!DOCTYPE html>
<html>
<head>
	<title></title>
</head>
<body>

<script type="text/javascript">
	
let str = "hello world!";

console.error(str.startsWith("hello"));
console.error(str.endsWith("!"));
console.error(str.includes("o"));

console.error("-------------------------");

console.error(str.startsWith("world", 6));
console.error(str.endsWith("hello", 5));
console.error(str.includes("hello", 6));

</script>

</body>
</html>